This invention relates to indicating apparatus; and more particularly to apparatus for indicating frost line depth.
When apparatus such as electronics gear or electrical cable, certain pipes and the like are buried in the ground it is often desirable, and in some cases necessary, that these objects be buried at a depth which is below the normal frost line of the ground in that area. In order to know to what depth such devices must be buried, one has to know the depth of the frost line for that area. For many areas the frost line depth for the coldest months has been established as generally being deeper than a given depth. Such a general depth measurement is satisfactory for many purposes and is often the depth below which local ordinances require that certain devices such as electrical cables must be buried.
While a general frost line depth is satisfactory for many purposes, there are applications that require more specific information. That is, there are instances where one needs to know to a reasonable degree of accuracy the frost line depth of the ground in a particular area during a given period of time. For example, in certain applications it may be necessary to determine the effects of freezing upon buried electronics gear. One may want to know the physical effects of freezing upon such electronics gear and/or what effects freezing has upon the performance parameters of the electronics gear. In order to obtain such test data, one needs to have accurate frost line depth measurements. There are, of course, other applications where accurate frost line depth measurements are needed.
In the past, thermocouple systems have generally been used to obtain accurate frost line depth measurements. These prior art thermocouple systems provide accurate frost line depth measurements and generally operate in a satisfactory manner. However, skilled personnel are generally needed to install and operate such thermocouple systems. Further, if a relatively large area is to be investigated by making a plurality of depth measurements, these prior art thermocouple systems become rather complex, thereby further increasing the difficulty of installation and operation and are relatively costly. Thus, a need for frost line depth measurement apparatus that is readily installed, is relatively inexpensive, and easily operated existed. This invention provides such frost line depth measurement apparatus.
The apparatus of this invention is inexpensive to manufacture, can be installed and operated by unskilled personnel and provides accurate frost line depth measurements. Further, the apparatus is reuseable and can readily be removed from one area and installed in another area.